diff --git a/core-modules/02QubesTemplateHVm.py b/core-modules/02QubesTemplateHVm.py
index eb5b309ee..d1d6e4595 100644
--- a/core-modules/02QubesTemplateHVm.py
+++ b/core-modules/02QubesTemplateHVm.py
@@ -70,6 +70,7 @@ def is_template(self):
     def is_appvm(self):
         return False
 
+    @property
     def rootcow_img(self):
         return self.storage.rootcow_img